Minimally invasive surgical procedures are desirable because such procedures can reduce pain and provide relatively quick recovery times as compared with conventional open medical procedures. Many minimally invasive procedures are performed with an endoscope. Such procedures permit a physician to position, manipulate, and view medical instruments and accessories inside the patient through a small access opening in the patient's body. Laparoscopy is a term used to describe such an “endosurgical” approach using an endoscope (often a rigid laparoscope). In this type of procedure, accessory devices are often inserted into a patient through trocars placed through the body wall.
Still less invasive treatments include those that are performed by inserting an endoscope through a natural body orifice to a treatment site. Examples of this approach include, but are not limited to, cystoscopy, hysteroscopy, esophagogastroduodenoscopy, and colonoscopy. Many of these procedures employ the use of a flexible endoscope during the procedure. Flexible endoscopes often have a flexible, steerable articulating section near the distal end of a shaft that can be controlled by the user by utilizing controls at the proximal end.
Some flexible endoscopes are relatively small (1 mm to 3 mm in diameter), and may have no integral working channel. Other flexible endoscopes, including gastroscopes and colonoscopes, have integral working channels having a diameter of about 2.0 to 3.5 mm for the purpose of introducing and removing medical devices and other accessory devices to perform diagnosis or therapy within the patient. Certain specialized endoscopes are available, such as large working channel endoscopes having a working channel of 5 mm in diameter, which can be used to pass relatively large accessories. Other specialized endoscopes include those having two working channels.
Many accessories, sheaths, overtubes, attachments, and other types of medical apparatuses have been developed for use with endoscopes for various purposes. For example, overtubes that cover the shaft of the endoscope have been developed to help keep the endoscope clean or to provide auxiliary endoscopic passageways or guides into the patient's body. Some of these apparatuses include an attachment device or end cap that may be affixed to the endoscope tip. Some end caps may be clamped or pressed tightly onto the endoscope tip. See, e.g., U.S. patent application Ser. No. 10/440,957 entitled “Medical Apparatus for Use with an Endoscope” to Stefanchik et al., filed May 16, 2003. Separate accessory channels have also been developed for use in conjunction with a conventional endoscope to facilitate the introduction of additional surgical tools or accessories.
Medical instruments introduced into a patient using a multi-channel endoscope emerge from the working channels in a direction generally parallel to the axis of the endoscope. This orientation of the instruments may be problematic for procedures in which surgical tasks (e.g., retraction and cutting) are required to be performed simultaneously at different angles relative to the longitudinal axis of the endoscope. Additionally, while the ability to apply a distally-directed force to an area of the treatment site using the distal end of the endoscope could be potentially useful for certain procedures, generating such force by pushing a flexible endoscope from its proximal end has heretofore proved difficult, as these instruments typically lack the stiffness and rigidity necessary to effectively transfer the pushing force over the instrument's length. What is needed is an improvement over the foregoing.